Hydrochemical characteristics of the Gallikos River water, Prefecture of Kilkis, Greece

Abstract

The Gallikos river basin is located in the northern part of Greece and discharges into the Thermaikos Gulf, North Aegean sea. Three main tributaries contribute to the river, the basin of which has a total areal extent of 930 km2. The basin of Gallikos river is formed of metamorphic rocks, limestones, Neogene and Quaternary deposits. Groundwater resources are mainly located within the carbonate rocks and the quaternary deposits. Water quality deterioration is documented based on the performed hydrochemical analyses of samples collected along the river course and its tributaries during the end of the wet and the dry seasons of year 2004. Results were correlated to the groundwater quality as this is reflected by analyses conducted on samples collected from wells adjacent to the river over the same periods. Samples were analyzed for major ions, nitrates, BOD5, COD, heavy metals and boron, whilst in situ measurements of pH, electrical conductivity and water temperature were performed. River water quality is related to the flow regime and is influenced by the geological structure, agricultural activities, as well as by untreated waste effluent that is discharged from villages and small industrial units that are scattered along the river basin.